The invention relates to an air vehicle concept that simultaneously provides a load bearing and antenna function, herein referred to as a Slotted Waveguide Antenna Stiffened Structure (SWASS) concept. SWASS uses airframe construction, such as hat shaped cross-section stiffened skins, or sandwich stiffened structure skin made from materials such as carbon fiber reinforced composites or aluminum. SWASS uses slot apertures in the skin as RF radiators and the top-hat stiffeners for both structural reinforcement and also as waveguides to feed the slot apertures. In this way, with minimal changes to load bearing skin configuration, these skins may also become RF apertures. This invention provides an opportunity to incorporate extremely large RF arrays in airborne vehicles by making the wing and/or fuselage skins function as antennas, with minimal weight impact to the air vehicle system.
The invention is an important breakthrough that merges high performance aircraft composite structure technology with high performance radio frequency (RF) slotted waveguide technology in a totally unique and novel concept. This concept is a marriage of two distinct and diverse technology areas. The SWASS concept offers a major improvement in several performance parameters for airborne RF apertures because the antenna is also a high performance structure. The SWASS concept will enable apertures of unprecedented size which offers the potential for major improvements in RF system performance. The SWASS concept allows integration of RI apertures in locations such as wing/fuselage skins and empennage structure that are impossible or prohibitively impractical for conventional non-structural slotted waveguides enabling unprecedented fields of view which may be important for future airborne RF systems. The SWASS concept is inherently low cost as it reduces the weight and part count needed for integration.
The Air Force has a long-term vision to develop Battlespace Total Situational Awareness and Information Dominance for maximum strategic and tactical advantage over any potential adversary. This vision requires an extensive radio frequency (RF) antenna suite to perform radar, surveillance, electronic warfare, data link, communication, navigation, and identification functions. Current antenna installations are limited to parasitic and non-load bearing installations inhibiting preferred vehicle integration locations and antenna size. This invention provides application opportunity to most Air Force air vehicle systems. This includes small uninhabited air systems, small surveillance aircraft, fighter aircraft and large transport aircraft. The ability to put very large antennas on relatively small aircraft will provide in theatre surveillance and reconnaissance operations from relatively inexpensive aircraft. This invention concept is applicable to a wide variety of frequencies and may be limited at lower frequencies by the large size of the waveguide required. This invention further has potential for broad application on commercial transport systems such as automobiles, trucks, buses, aircraft, boats, yachts, and ships. These applications may be driven by the need for electromagnetic data links that provide a wide variety of safety, logistics, and entertainment information. The nature of this invention may facilitate conformal integration directly into the structure of commercial vehicles in the same fundamental manner as the invention will be integrated into Air Force air vehicles.